In many communication systems, communications networks are used to exchange messages among several interacting nodes which are separated apart in space. There are many types of networks which may be classified in different aspects. In one example, the geographic scope of the network could be over a wide area, a metropolitan area, a local area, or a personal area, and the corresponding networks are designated as wide area network (WAN), metropolitan area network (MAN), local area network (LAN), or personal area network (PAN). Networks may also differ in the switching/routing technique used to interconnect the various network nodes and devices (e.g. circuit switching, packet switching, etc.), in the type of physical media employed for waveform propagation (e.g. wired vs. wireless), or in the set of communication protocols used (e.g. Internet protocol suite, SONET (Synchronous Optical Networking), Ethernet, wireless LAN protocols, etc.).